Add migration code to change existing domain scoped content settings to be origin scoped

components/content_settings/core/browser/host_content_settings_map.cc

Index: components/content_settings/core/browser/host_content_settings_map.cc
diff --git a/components/content_settings/core/browser/host_content_settings_map.cc b/components/content_settings/core/browser/host_content_settings_map.cc
index 6b56ae6e7f863dec90f9a3cc482015fefa96ccb3..4983d5624ebed9ec2e0e444396ea28abdb1aa83b 100644
--- a/components/content_settings/core/browser/host_content_settings_map.cc
+++ b/components/content_settings/core/browser/host_content_settings_map.cc
@@ -497,6 +497,70 @@ void HostContentSettingsMap::MigrateKeygenSettings() {
   }
 }
 
+void HostContentSettingsMap::MigrateDomainScopedSettings() {
+  const ContentSettingsType kDomainScopedTypes[] = {
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      CONTENT_SETTINGS_TYPE_IMAGES,
+      CONTENT_SETTINGS_TYPE_PLUGINS,
+      CONTENT_SETTINGS_TYPE_JAVASCRIPT,
+      CONTENT_SETTINGS_TYPE_AUTOMATIC_DOWNLOADS,
+      CONTENT_SETTINGS_TYPE_POPUPS};
+  for (const ContentSettingsType& type : kDomainScopedTypes) {
+    if (!content_settings::ContentSettingsRegistry::GetInstance()->Get(type))
+      continue;
+    ContentSettingsForOneType settings;
+    GetSettingsForOneType(type, std::string(), &settings);
+
+    for (const ContentSettingPatternSource& setting_entry : settings) {
+      // Migrate user preference settings only.
+      if (setting_entry.source != "preference")
+        continue;
+      // Migrate ALLOW settings only.
+      if (setting_entry.setting != CONTENT_SETTING_ALLOW)
+        continue;
+      // Skip default settings.
+      if (setting_entry.primary_pattern == ContentSettingsPattern::Wildcard())
+        continue;
+
+      DCHECK(setting_entry.secondary_pattern ==

[msramek, 2016/06/30 16:16:21]

I would prefer

if (...) {
  NOTREACHED();
  continue;
}

If this DCHECK were false, SetContentSettingCustomScope(..., Wildcard()) could
accidentally allow something that wasn't allowed.

Besides, how do we know that this must be true? We're reading content settings
from the user's Preferences file; a single call of SetContentSetting() with
secondary_pattern != Wildcard() in a years-old version of Chrome could break
that expectation.

[lshang, 2016/07/04 02:46:00]

Done. Fair enough.

+             ContentSettingsPattern::Wildcard());
+
+      ContentSettingsPattern origin_pattern;
+      if (!ContentSettingsPattern::MigrateFromDomainToOrigin(
+              setting_entry.primary_pattern, &origin_pattern)) {
+        continue;
+      }
+
+      if (!origin_pattern.IsValid())
+        continue;
+
+      GURL origin(origin_pattern.ToString());
+      DCHECK(origin.is_valid());
+
+      // Ensure that the current resolved content setting for this origin is
+      // allowed. Otherwise we may be overriding some narrower setting which is
+      // set to block.
+      ContentSetting origin_setting =
+          GetContentSetting(origin, origin, type, std::string());
+
+      // Remove the domain scoped pattern. If |origin_setting| is not
+      // CONTENT_SETTING_ALLOW it implies there is some narrower pattern in
+      // effect, so it's still safe to remove the domain-scoped pattern.
+      SetContentSettingCustomScope(setting_entry.primary_pattern,
+                                   setting_entry.secondary_pattern, type,
+                                   std::string(), CONTENT_SETTING_DEFAULT);
+
+      // If the current resolved content setting is allowed it's safe to set the
+      // origin-scoped pattern.
+      if (origin_setting == CONTENT_SETTING_ALLOW)
+        SetContentSettingCustomScope(
+            ContentSettingsPattern::FromURLNoWildcard(origin),
+            ContentSettingsPattern::Wildcard(), type, std::string(),
+            CONTENT_SETTING_ALLOW);
+    }
+  }
+}
+
 void HostContentSettingsMap::RecordNumberOfExceptions() {
   for (const content_settings::WebsiteSettingsInfo* info :
        *content_settings::WebsiteSettingsRegistry::GetInstance()) {